电子标签技术及应用

介绍了电子标签的技术原理、特性及分类,比较了电子标签与其他几种识别技术的区别,综述了电子标签在安全防伪、防盗以及供应链管理等方面的应用现状,指出了电子标签存在的问题,提出了我国电子标签发展的建议.     

激烈竞争的电子标签技术谁主沉浮(三)

阐述电子标签的广泛应用和市场需求,分析射频识别技术的优势和网版印刷天线的要点。     

无线射频电子标签(RFID)的自动化测试系统

无线射频电子标签识别技术可以用来识别在一定范围内的物体并可实现物流追踪,在现代生产生活中有着较为广泛的应用。本文笔者将对无线射频识别技术进行简要分析,并对无线射频电子标签的自动化检测系统作具体分析和研究。     

纵观RFID技术

世界各地都在关注射频识别标签RFID（电子标签）技术，并预测它的增长趋势。RFID标签真的能取代条形码吗？下面我们就来分析一下RFID技术及其利弊。     

电子标签市场需求已成规模

在近日举办的北京国际标签产业及喷墨技术高峰论坛上,中国RFID联盟理事长张琪宣布,统计数字显示,2008年中国RFID（射频识别）市场规模巳达65．8亿元,这表示RFID的市场需求已形成规模。她预测,RFID有望成为印刷业者和油墨制造商的一个新兴市场,将为印刷企业带来巨大商机。     

两岸三地电子标签产业联盟正式成立

近日,大陆、台湾和香港的RFID产业正式结盟,三地150多名业界人士参加了成立仪式。 RFID是射频识别技术的英文缩写,俗称电子标签。该技术20世纪9O年代才开始兴起,并在门禁控制、动物身份识别、道路自动收费等方面得到广泛应用,备受零售商推崇。     

刺绣型超高频织物电子标签的开发

为开发穿戴舒适、形式隐蔽、应用便捷的柔性电子标签,文章以70D/24F×3镀银导电纱为基材将标签天线绣制在纯棉机织物上,并与标签芯片封装制得刺绣型织物电子标签,进而研究各刺绣工艺参数对织物电子标签电阻和读取性能的影响。结果表明:针迹类型、针迹间距、针迹长度等刺绣工艺参数分别通过改变导电纱与电流传输方向夹角、导电纱密度及落针点数量,影响织物电子标签性能。标签天线的适宜刺绣工艺参数为针迹间距0. 25～0. 40 mm、针迹长度2. 0～4. 0 mm的直线针,尤其当采用针迹间距0. 35 mm、针迹长度2. 0 mm的直线针时,织物电子标签读取距离最远可达7. 6 m。     

电子标签印刷

RFID(Radio Frequency Identification)的中文名称为射频识别技术,这一技术早在上世纪80年代初就由美国国防部和世界第一大商品零售商--沃尔玛公司首先提出并进行研究.目的是让人们通过采用一些先进的技术手段,实现对各类目标(人或物)在不同状态(静止、移动,甚至恶劣环境)下的自动识别和管理,从而实现商品生产过程中的控制,提高生产效率;实现商品流程过程中的控制,提高流通效率,减少商品流失现象;在安检部门可以实现无接触的安全检查;在交通部门可以实现对交通工具的实时监测等等.     

MEASUREMENT OF FLUID FOOD VISCOSITY USING MICROFABRICATED RADIO FREQUENCY COILS

We report on the use and applicability of microfabricated radio frequency (r.f.) coils for viscosity measurements of fluid foods. The viscosity of fluid milk and milklike products was measured using nuclear magnetic resonance imaging based on microfabricated r.f. coils coupled to in‐line tubing with an inner diameter of 1.4 × 10^‐3 m. The fluid's apparent viscosity ranged from 0.002 to 0.08 Pa·s. The magnetic resonance‐based measurements were limited in shear rate range because of the small size of the coil. Magnetic resonance‐based measurements from 2 to 15 s^‐1 were obtained and were equivalent to off‐line rotational rheometry.     

COMPUTER SIMULATION of CAPACITIVE RADIO FREQUENCY (RF) DIELECTRIC HEATING ON VEGETABLE SPROUT SEEDS

The application of a three‐dimensional finite‐element computer program package, TLM‐FOOD‐HEATING (FAUSTUS Scientific Corp., Victoria, Canada), on the simulation of capacitive radio frequency (RF) dielectric heating of radish and alfalfa seeds was investigated. Seeds placed inside polystyrene boxes were described as a rectangle, where nonuniform boundary conditions presented complications in the simulation. Temperature and moisture dependent thermal properties and temperature and frequency dependent dielectric properties of seeds were considered in the modeling. the time‐temperature profiles of seeds at different locations within the rectangle seeds boxes were simulated. the model was then validated using experimental data. Simulated temperature distribution in seeds was consistent with the measured results. the absolute temperature differences between simulated and measured values in radish seeds packed in a 100 × 25 × 50 mm rectangle seeds box were 1.8C, 1.1C, 8.9C, and 13.6C in the center, top, edge, and bottom locations, respectively, when seeds reached about 80C, and were 0.9C, 2.4C, 7.75C, and 14.3C, respectively, in alfalfa seeds box in the same conditions.     

USING CAPACITIVE (RADIO FREQUENCY) DIELECTRIC HEATING IN FOOD PROCESSING AND PRESERVATION – A REVIEW

Capacitive (Radio Frequency) dielectric heating has great potential for achieving rapid and uniform heating patterns in foods, providing safe, high quality food products. This review describes and discusses the major technology behind capacitive (RF) dielectric heating in food processing and preservation, the current applications of the technology in the industry, the potential use of mathematical modeling for heating system design, and the major challenges facing the use of this technology in food processing. A vast amount of work is still necessary to further understand the dielectric properties of both food and packaging materials in order to refine system design and maximize performance of this technology in the field of packaged food products. Various economic studies will also play an important role in understanding the overall cost and viability of commercial application of this technology in food processing.     

RADIO FREQUENCY PULSE APPLICATION FOR HEATING UNIFORMITY IN POSTHARVEST CODLING MOTH (LEPIDOPTERA: TORTRICIDAE) CONTROL OF FRESH APPLES (MALUS DOMESTICA BORKH.)

A radio frequency (RF) treatment, with a pulse mode to increase heating uniformity, was examined as a potential quarantine treatment against fifth instars of the codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae), in apples, Malus sylvestris L. var. domestica (Borkh.) Mansf., intended for export to Japan. Apples were exposed in water baths to 27.12‐MHz RF energy at 12 kW with a pulse mode of 30 s‐on/30 s‐off for different durations. The temperature uniformity was determined by measurements at 12 sites evenly spaced at two depths in the fruit. The most promising exposure time was 29 min. The efficacy of the treatment with the pulse mode was examined against the codling moth larvae by using exposures between 27 and 30 min and up to 30 min of holding time in bath after treatment. The treatment that killed all larvae with the least amount of energy was the 29‐min exposure with 50‐min holding time. This treatment was appraised for fruit quality in “Delicious” apples. Some injury was observed when treated fruits were removed from 1C storage after 30 days. When these fruits were held at 25C for 1 week, all were too damaged to evaluate for fruit quality. Although pulse mode increased heating uniformity in the fruit, the thermal requirements to control codling moth larvae may exceed the injury threshold of the fruits.     

RADIO FREQUENCY (RF) HEATING OF STARCH SOLUTIONS UNDER CONTINUOUS FLOW CONDITIONS: EFFECT OF SYSTEM AND PRODUCT PARAMETERS ON TEMPERATURE CHANGE ACROSS THE APPLICATOR TUBE

Studies were conducted to evaluate the effect of system and product parameters on the temperature change (ΔT) across a 1.5 kW radio frequency heater operating at 27.12 MHz. Starch solutions (1 to 4% w/w) were used at three different flow rates (0.35, 0.5 and 1 L/min) and four power levels (672, 912, 1152 and 1392 W). The average heating rate of starch solutions varied from 6 to 19C/min depending on flow rate, concentration and power level. The corresponding residence time varied from 1.5 to 4.3 min. Central composite designs involving power (830 to 1234 W) and starch concentration (1 to 4% w/w) at 0.5 L/min were used to study the effects of salt, pH and sugar. As expected fluid flow rate, power level and salt concentration had significant impact (P ± 0.05) on temperature change (ΔT) across the applicator tube. Although the interaction effect of salt and concentration influenced ΔT (P < 0.05), observed trends were not clear cut. Sugar and pH had no significant (P >0.05) influence on ΔT due probably to their relatively lower conductivities. However, the interaction effect of sugar and starch concentration affected ΔT. Correlations were developed for estimating ΔT across the tube as a function of power level, concentration, pH, added salt and sugar. Finally, dimensionless correlations involving the generalized Reynolds, Prandtl, Grashof numbers, dimensionless power and loss‐factor ratios were developed for estimating the temperature ratio (U) across the RF applicator.     

翡翠辨（之一）

对于翡翠名称的辨正以及严谨的历史考证，至今仍存在一定的误区。通过对众多古籍中有关翡翠的详尽描述和其名称反复被引用的研究，从翡翠称谓的语法关系、语境特征来找寻其真正含义的证据，进而，阐述了我国历史上翡翠名称的种种不同，并证明了关于宋朝翡翠名称实为“青金”的观点。     

翡翠辨（之二）

阐述对翡翠历史和文化研究的紧迫性，认为翡翠专用术语的辨析及统一有利于珠宝专业知识的对外交流，详细地论述了近代翡翠名称与实际，以及在行地剖析了近代翡翠的专用术语。     

水晶鉴定方法的探讨

据多年鉴定水晶的实践经验，阐述了日常对水晶的原石、普通饰品、贵重饰品及优化处理品的鉴定步骤与方法。